The width of the vehicle influences on passanger's inner room as well as stability of driving. The Opel is 5 % wider when compared to the Infiniti M I. It is often clearly perceptible by those sitting in front, who have more room for their elbows.
The Opel has 65 mm longer wheelbase in comparison to Infiniti M I 4.5 V8 340HP. Therefore the Opel Commodore C Estate is more safe and has a better stability. What is more, longer wheelbase influences on convenient and more comfortable driving.
Number of doors
A five-door car generally means a hatchback and as a result the Opel Commodore C Estate, which whole rear including the window lifts up and the rear seats folds flat enlarging a luggage compartment, has an advantage over the 4-door Infiniti M I which in turn has smaller lid and a partition behind the rear seats.
The higher a car is, the better is the comfort of getting in to it and greater possibility of carrying massive amount of luggage to it. The difference at the level of 11 % in favor of the Opel is little and does not matter much.